Crash. In plum Corkonian tones, a middle-aged man boasts of his success in the brain-surgery business. Suddenly his listener — a younger man in drag — ducks out of his wig and reappears in a false moustache. Bang. As the Corkman drones on to the now untenanted wig, two small boys appear with a dead dog impaled on a tent pole. And wallop.

Welcome to Walsh World. The terrain is familiar but disconcerting. We see all the elements of a classic farce — coincidence, frenetic action, multiple mistaken identities and clockwork plotting. But something sinister is lurking in this particular clock: savagely dysfunctional families, rituals, enclosed worlds. All the subjects, in fact, that have preoccupied Enda Walsh since his early plays such as Disco Pigs and The Ginger Ale Boy.

But The Walworth Farce — Walsh’s latest play, and his first production with Druid — also incorporates some striking new developments. Walsh operates within the strictures of theatrical farce, blending its high-tempo slapstick style with his own deeper and darker concerns. The result is a technical tour-de-force, and a remarkable theatrical development — yet, paradoxically, it also raises questions about his limitations as a playwright.

It is a truism that lesser writers borrow while great ones steal. On this evidence, Walsh is still somewhere in between. His ear for linguistic nuances has always been striking. A Dubliner who spent his formative writing years in Cork, Walsh has previously mined the city’s patois to great effect. Since moving to London a couple of years ago, he has clearly been busy absorbing that city’s language.

In The Walworth Farce he attempts to bring the two together. The central character, Dinny, played by Denis Conway, is a Corkman apparently living in a high-rise estate in London’s Walworth. Without giving too much of Walsh’s intricate plot away, it is clear that Dinny is a premier-division fantasist. Is he simply another Irish emigrant whose longing for the old sod has led him to create an enclosed fantasy life, into which he has drawn his two teenage sons, Blake and Sean? The plot is tortuously complicated but in essence involves Dinny re-enacting, over and over, a turbulent incident from the family history, with his sons forced to play the supporting roles.

The director, Mikel Murfi, has wide experience of physical theatre and mime, notably as an actor and director with companies such as Barabbas. This experience ensures Walsh’s plotting works perfectly, conforming to all that we expect of a well-tuned farce. But Walsh also uses the form to pose questions about family relationships, personal memory, sanity and self. In glimpses of some altogether blacker world, we see that the farce structure itself is Dinny’s construct, a virtual universe that he has created for his sons in order to indoctrinate them and force their submission.

Both classic farce — as employed by, for instance, Alan Bennett — and Walsh’s earlier plays require a turning point: some extraneous element or person who intrudes, upsetting all the apple carts. Here it comes in the form of Hayley (Syan Blake), a supermarket worker from Tesco who knocks innocently at the door at the end of the first act. Her intrusion — to which the three men respond in different ways — is the beginning of the end for Dinny’s artificial reality.

Disco Pigs, Walsh’s breakthrough play in international terms, had great linguistic and psychological density. It succeeded because the emotional truth beneath the dialect had such a latent, coiled vitality.

Walsh goes easier on the dialect here. Dinny may have a Cork accent and make regular recourse to tribal emblems such as the “blood and bandage” (the red and white of Cork’s sporting colours), but there is relatively little local slang. Instead there are other kinds of density: a multi- layered structure where several things happen at once and a vast range of reference and allusion. There are echoes of Beckett and Pinter, as well as Bennett and Joe Orton. The relentless physicality of the action is supported and echoed by Walsh’s trademark linguistic panache. And he has also learnt something about the effective use of silence on stage.

Yet, for all his virtuosity, Walsh hesitates on the threshold. He has begun to appropriate London as he once appropriated Cork, and his grasp of psychological disturbance is acute. But at key moments he opts to be merely clever, at points where a great farceur — such as Orton — would have gone for the jugular.

For example, the fact that Hayley happens to be black is thrown away on a weak visual joke. Walsh missed an opportunity here to intensify the disturbing subtexts and target the latent racism of his scenario. He wants to have it both ways: to lampoon mercilessly, and still be seen as a nice guy who has moved beyond such petty themes as race.

The Druid production is typically impressive, with strong performances from Conway, plus Garrett Lombard and Aaron Monaghan as his sons. The part of Hayley is under-written, but Blake makes an impression nonetheless.

Behind the cleverness and the half-formed satire there remains a core of pure originality. This is the true Walsh World: an uneasy amalgam of solitary children, damaged parents and twisted relationships. All this was visible more than 10 years ago in The Ginger Ale Boy, was concentrated in Bedbound, and hit a magic streak in Disco Pigs. Here it takes a quirky sidestep: technically proficient, but no closer to unearthing its own deepest and darkest secrets.

Walsh is still a writer with huge potential. On this evidence, however, he has yet to make the quantum leap beyond that. In terms of entertainment value, however, The Walworth Farce is among his best plays. If he can fine-tune the relationship between audience appeal and his darker themes he may yet become a force to be reckoned with.

The Walworth Farce, The Helix, Dublin, until April 15